A256813 - OEIS

A256813

Number of length n+5 0..1 arrays with at most two downsteps in every 5 consecutive neighbor pairs.

63, 124, 245, 484, 956, 1888, 3728, 7362, 14539, 28712, 56701, 111974, 221128, 436688, 862380, 1703044, 3363203, 6641716, 13116185, 25902088, 51151928, 101015784, 199487860, 393952358, 777984487, 1536378320, 3034068649

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OFFSET

1,1

COMMENTS

Column 5 of A256816.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 2*a(n-1) -a(n-2) +2*a(n-3) -a(n-4) +2*a(n-5) -a(n-6).

Empirical g.f.: x*(63 - 2*x + 60*x^2 - 8*x^3 + 48*x^4 - 32*x^5) / (1 - 2*x + x^2 - 2*x^3 + x^4 - 2*x^5 + x^6). - Colin Barker, Jan 24 2018

EXAMPLE

Some solutions for n=4:

..1....1....0....0....0....1....0....1....1....1....0....1....0....1....0....1

..1....0....1....1....1....0....1....1....0....0....0....0....0....1....0....0

..0....0....1....1....1....0....0....0....0....1....0....0....1....1....1....0

..0....0....0....1....0....0....1....0....0....1....0....1....0....1....0....0

..0....0....0....0....0....0....1....0....1....1....1....1....0....1....1....0

..1....1....1....0....1....0....0....0....0....0....1....0....1....1....1....1

..1....0....1....0....0....1....1....0....1....0....1....0....1....0....1....0

..0....1....1....1....1....0....0....1....1....0....0....0....0....0....1....0

..1....1....0....0....1....0....0....0....1....0....0....0....1....1....1....0

CROSSREFS

Cf. A256816.

Sequence in context: A274460 A181556 A096023 * A324488 A080947 A023720

Adjacent sequences: A256810 A256811 A256812 * A256814 A256815 A256816

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 10 2015

STATUS

approved